Terminal block cover with nut retention feature

ABSTRACT

A terminal block cover includes a base having a base surface configured to be secured against a terminal block. First and second spaced apart sidewalls extend from and adjoin the base. An outer wall is spaced apart from the base and is secured to the base by and adjoins with the first and second sidewalls. A lateral wall is arranged at a first lateral side and extends between and adjoins the first and second sidewalls, the outer wall and the base, which together provide at least one terminal pocket. An inner surface is provided on the outer wall facing the terminal pocket and has first and second surfaces. The first and second surfaces are at first and second distances respectively from the base surface, and the first distance is greater than the second distance. The second surface retains a terminal nut.

BACKGROUND

This disclosure relates to a terminal block assembly, and moreparticular, to a terminal block assembly for use on a gas turbine enginegenerator.

On a gas turbine engine generator application, a terminal block cover isoften used to protect the phase terminals for maintenance personnelsafety and to protect the phase leads from foreign object debris thatcould cause shorting. In the past, copper leads with lugs at their endshave been secured to the terminals. For new applications, aluminum leadsare used to reduce weight. Aluminum wire has a higher resistivity thancopper wire given the same gage size wire. In order to compensate forthe higher resistance of the aluminum wire, a larger gage aluminum wireis used which requires a correspondingly larger lug.

SUMMARY

A terminal block cover includes a base having a surface configured to besecured against a terminal block. First and second spaced apartsidewalls extend from and adjoin the base. An outer wall is spaced apartfrom the base and is secured to the base by and adjoins with the firstand second sidewalls. A lateral wall is arranged at a first lateral sideand extends between and adjoins the first and second sidewalls, theouter wall and the base, which together provide at least one terminalpocket. An inner surface is provided on the outer wall facing theterminal pocket and has first and second surfaces. The first surface isadjacent the second lateral side, and the second surface is providedinboard from the first surface toward the first lateral side. The firstand second surfaces are at first and second distances respectively fromthe base surface, and the first distance is greater than the seconddistance.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be further understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view of an example gas turbine engine.

FIG. 2 is a perspective view of a generator with a terminal blockassembly.

FIG. 3 is a perspective view of the generator with an exploded view ofthe terminal block assembly.

FIG. 4 a is a cross-sectional view of the terminal block assembly with aterminal block cover in a first installed position.

FIG. 4 b is a cross-sectional view of the terminal block assembly withthe terminal block cover in a second installed position.

FIG. 5 a is a bottom elevational view of the terminal block cover.

FIG. 5 b is a cross-sectional side elevational view of the terminalblock cover.

FIG. 5 c is a top/side perspective view of the terminal block cover.

FIG. 5 d is a bottom/side perspective view of the terminal block cover.

DETAILED DESCRIPTION

An example gas turbine engine (GTE) 10 is shown in FIG. 1. The GTE 10illustrated is a high bypass configuration having a core nacelle 12driving a fan (not shown) housed within a fan nacelle 14. Thearrangement shown includes forward and rearward variable frequencygenerator assemblies 16, 18, each having a common generator 20.

Referring to FIGS. 2 and 3, the generator 20 includes a housing 22 onwhich a terminal block assembly 24 is supported. The terminal blockassembly 24 includes a terminal block 26 fastened to the housing 22. Theterminal block 26 provides multiple terminals 28 to which lugs 46 areconnected. Wires 62 electrically connect the lugs 46 to an electricalcomponent 64, as shown in FIG. 4 a. The terminal block 26 includesterminal studs 30 at each terminal 28, and a lug 46 is secured to itsrespective terminal stud 30 by a nut 48 having a nut height W (FIG. 4b). In one example, the nut 48 is a SPIRALOCK nut.

Referring to FIGS. 3 and 4 a, each terminal stud 30 is electricallyconnected to a stator 36 within the housing 22 by via a terminal lead34. A rotor 38, rotationally driven by a spool 42 through a gearbox 40,imparts a current in the stator 36. The terminal lead 34 has a bracket32 received on the terminal stud 30, which is clamped between a washer44 and the lug 46. The lug 46 includes an aperture 66 that received anend of the wire 62.

A terminal block cover 50 is secured over the terminals 28 to protectmaintenance personnel and prevent foreign object debris from shortingthe terminals. In one example, fasteners 52 are received in a respectivehole 54 in ears at opposite corners of a base 56 of the terminal blockcover 50 and secured to a corresponding threaded hole 60 in the terminalblock 26, as best shown in FIG. 2. The terminal block cover 50 isconfigured such that it can be secured to the terminal block 26 ineither of first and second installed positions (FIGS. 4 a and 4 b) whenrotated 180 degrees, which can accommodate wires secured to the terminalblock 26 from either side. A washer 58 is provided between each fastener52 and the terminal block cover 50 in the example shown.

The base 56 has a base surface 68 is secured against the terminal block26. Referring to FIGS. 4 a-5 d, first and second spaced apart sidewalls74, 76 extend from and adjoin the base 56. An outer wall 72 is spacedapart from the base 56 and secured to the base 56 by and adjoins withthe first and second sidewalls 74, 76. A lateral wall 78 is provided ata first lateral side 77 and extends between and adjoins the first andsecond sidewalls 74, 76, the outer wall 72 and the base 56, whichtogether provide at least one terminal pocket 82. The terminal blockcover 50 provides a rectangular box-like integral structure, which ismolded from a non-metallic material (TORLON is one example).

An inner surface 86 is provided on the outer wall 72 and faces thepocket 82. The inner surface 86 has first and second surfaces 88, 90.The first surface 88 is adjacent a second lateral side 79 opposite thefirst lateral side. The second surface 90 provided inboard from thefirst surface 88 toward the first lateral side 77. The first and secondsurfaces 88, 90 are at first and second distances D1, D2 respectivelyfrom the base surface 68. The first distance D1 is greater than thesecond distance D2. In one example, the ratio of D1/D2 is approximately1.2. In one example, D1 is approximately 1.245 inch (31.623 mm), and D2is approximately 1.035 inch (26.289 mm).

In the example, the lateral wall 78 is generally uninterrupted andsubstantially encloses the pocket. In one example, the lateral wall 78includes an edge 80 that is slightly spaced from the terminal block 26when the terminal block cover 50 is in the installed position. Thesecond lateral side 79 is generally exposed and receives the lug 46,which extends into the pocket 82. In one example, partition walls 84extend outward from the inner surface 86 and the lateral wall 78 toprovide discrete pockets 82 for each of the lugs 46. The lug 46 isnearer the first surface 88 than the second surface 90.

The first and second surfaces 88, 90 are respectively at first andsecond distances T1, T2 taken from a terminal end 92 of the terminalstud 30 parallel to its axis A. The first distance T1 (0.335 inch (8.509mm), for example) is greater than the second distance T2 (0.125 inch(3.175 mm), for example). With the terminal block cover 50 in theinstalled position, the second distance T2 (approximately 0.125 inch(3.175 mm), for example) is less than the nut height W (0.282 inch(7.163 mm), for example) from the terminal end 92. The ratio of nutheight to the second distance (W/T2) is approximately 2.256 inch (57.302mm) in one example.

The inner surface 86 includes a width that extends from the second side79 to the lateral wall 78 such that the width is offset relative to theterminal stud 30, which can be seen in FIGS. 4 a and 4 b. The secondsurface 90, which retains the terminal nut 48, overlaps more of theterminal end 92 in the first installed position, shown in FIG. 4 a.However, the second surface 90 sufficiently overlaps the terminal nut 48in the second installed position, shown in FIG. 4 b.

Although an example embodiment has been disclosed, a worker of ordinaryskill in this art would recognize that certain modifications would comewithin the scope of the claims. For example, the dimensions provided inthis disclosure are nominal. For that reason, the following claimsshould be studied to determine their true scope and content.

What is claimed is:
 1. A terminal block cover for a terminal blockassembly, the terminal block cover comprising: a base having a basesurface configured to be secured against a terminal block; first andsecond spaced apart sidewalls extending from and adjoining the base; anouter wall spaced apart from the base and secured to the base by andadjoining with the first and second sidewalls; a lateral wall at a firstlateral side and extending between and adjoining the first and secondsidewalls, the outer wall and the base, which together provide at leastone terminal pocket; and an inner surface provided on the outer wallfacing the terminal pocket and having first and second surfaces, thefirst surface adjacent the second lateral side, and the second surfaceprovided inboard from the first surface toward the first lateral side,the first and second surfaces at first and second distances respectivelyfrom the base surface, the first distance greater than the seconddistance.
 2. The terminal block cover according to claim 1, wherein thelateral wall is generally uninterrupted and substantially encloses theterminal pocket, and the second lateral side is generally exposed andconfigured to receive at least one electrical lead lug.
 3. The terminalblock cover according to claim 2, wherein partition walls extendoutwardly between the inner surface and the lateral wall to providediscrete pockets.
 4. The terminal block cover according to claim 1,wherein the first and second sidewalls, the outer wall and the lateralwall provide a rectangular, box-like integral structure.
 5. The terminalblock cover according to claim 4, wherein the base includes an earextending outwardly from each of the first and second sidewalls and awayfrom the pocket at opposite corners.
 6. The terminal block coveraccording to claim 1, wherein the ratio of the first distance to thesecond distance is approximately 1.2.
 7. The terminal block coveraccording to claim 6, wherein the first distance is approximately 1.245inch (31.623 mm) and the second distance is approximately 1.035 inch(26.289 mm).
 8. A terminal block assembly comprising: a terminal blockhaving a terminal stud extending along an axis to a terminal end andconfigured to electrically connect to a generator; a terminal nutthreadingly secured to the terminal stud, the nut having a nut height; aterminal block cover including a base secured to the terminal block, anouter wall spaced apart from the base and secured to the base by andadjoining with at least one wall, the outer wall and the at least onewall providing at least one terminal pocket; and an inner surfaceprovided on the outer wall and facing the terminal nut and having firstand second surfaces, the first and second surfaces respectively at firstand second distances taken from the terminal end and parallel to theaxis, the first distance greater than the second distance, and thesecond distance less than the nut height from the terminal end.
 9. Theterminal block assembly according to claim 8, wherein the at least onewall includes first and second sidewalls extending from and adjoiningthe base, and a lateral wall at a first lateral side adjoining the firstand second sidewalls and the outer wall to provide a rectangular,box-like integral structure.
 10. The terminal block assembly accordingto claim 9, wherein the lateral wall is generally uninterrupted andsubstantially encloses the terminal pocket, and a second lateral sideopposite the first lateral side is generally exposed and configured toreceive at least one electrical lead lug.
 11. The terminal blockassembly according to claim 10, wherein partition walls extend outwardlybetween the inner surface and the lateral wall to provide discretepockets.
 12. The terminal block assembly according to claim 10, whereina lug is provided in one of the discrete pockets and secured to theterminal stud with the terminal nut, the lug nearer the first surfacethan the second surface.
 13. The terminal block assembly according toclaim 8, wherein the inner surface includes a width extending from thesecond side to the lateral wall, the width offset relative to the axisproviding first and second installed positions of the terminal blockcover relative to the terminal block.
 14. The terminal block assemblyaccording to claim 13, wherein the second surface overlaps more of theterminal end in the first installed position than the second installedposition.
 15. The terminal block assembly according to claim 8, whereinthe ratio of nut height to the second distance is approximately 2.256inch (57.302 mm).
 16. The terminal block assembly according to claim 15,wherein the nut height is approximately 0.282 inch (7.163 mm) and thesecond distance is approximately 0.125 inch (3.175 mm).
 17. A generatorcomprising: a housing enclosing a stator and a rotor; a terminal blockassembly mounted to the housing, the terminal block housing including aterminal block having terminals with terminal studs electricallyconnected to the stator by terminal leads having lugs secured to theterminal studs with terminal nuts; and a terminal block cover having anouter wall with an inner surface facing the terminal studs, an innersurface having first and second surfaces that are respectively at firstand second distances from an end of the terminal stud, the firstdistance greater than the second distance, and the second distance lessthan a nut width of the terminal nut from the terminal stud.
 18. Thegenerator according to claim 17, wherein the inner surface includes awidth extending from the second side to the lateral wall, the widthoffset relative to the terminal stud providing first and secondinstalled positions of the terminal block cover relative to the terminalblock, the lugs nearer to the first surface than the second surface. 19.The generator according to claim 18, wherein the second surface overlapsmore of the terminal end in the first installed position than the secondinstalled position.
 20. A method of assembling a terminal block assemblycomprising the steps of: a) securing a terminal lead lug to a terminalstud using a terminal nut; b) positioning a terminal block cover overthe terminal lead lug, the terminal block cover including a innersurface opposite and facing the terminal stud, the inner surfaceincluding first and second surfaces with the first surface arranged overthe lug, the second surface in closer proximity to the terminal nut thatthe first surface; and c) securing the terminal block cover relative tothe terminal block to prevent the terminal nut from dislodging from theterminal stud.